Optimisation of photosynthesis for environmental fitness is one of the most important approaches to increase productivity and acclimate plants to unfavourable environmental conditions. In this paper, the pathways of optimisation of photosynthesis are considered using novel tools both at the level of an individual plant and plant communities. Fast acclimation of photosynthetic apparatus to the environmental stresses and fluctuations of light intensity and light quality plays an important role in supporting effective photosynthesis. The bioengineered photosynthetic systems responsible for energy dissipation (non-photochemical quenching) and stomatal functioning, as well as some enzymes of CO2 fixation system alongside with introduction of effective mechanisms found in algae or cyanobacteria into chloroplasts, can be used for conservation of effective photosynthesis during such fluctuations. The conversion of some C3 crops grown in hot and arid climates into C4 plants may be a goal for the future. Special focus has been directed towards the detailed description of the photosynthetic optimisation under stress conditions taking into account the specifics of the most common stress factors.